Estimation of land vehicle roll and pitch angles

In this article, two kinematics-based observers are proposed to estimate the vehicle roll and pitch angles by using an inertial measurement unit. The observers are mathematically proven to be stable if the vehicle yaw rate is not zero. With a design variation of the observer gains, the estimated roll or pitch angle is shown to further asymptotically converge to the true value, eliminating possible errors caused by the biases of the acceleration signals. Simulation results show that accurate estimation of both pitch and roll angles can be achieved without the help of external sensors such as global positioning systems, either by using the accelerometer-based reference pitch or roll angle as the maneuver varies, or by using an observer with zero steady-state error property.     

Numerical modelling of fish eggs dispersion at the Patos Lagoon estuary — Brazil

The Patos Lagoon estuary is the most important nursery ground for commercially relevant species of fish and crustaceans in the South of Brazil, maintaining fisheries that sustain 3500 fisher families throughout the Rio Grande do Sul State coastline. Around 80% of the interior estuarine area is very shallow (< 2 m), and recruitment of fish eggs and larvae to the inner parts of the Patos Lagoon estuary is directly related to the circulation pattern in the area, which is controlled by local and non-local wind effects and freshwater discharge. The objective of this study is to investigate the processes controlling the transport of estuarine dependent fish eggs between the Atlantic Ocean and the Patos Lagoon estuary.An integrated numerical system based on a bi-dimensional hydrodynamic model and a Lagrangean transport model of passive particles is applied to a selection of scenarios representing the passage of weather fronts over the area. At this stage, fish eggs are represented as buoyant passive particles. Modelling results are compared against field data for the period under investigation (September/October 1999) and historical records. Short term results are analysed in terms of the meteorological conditions (wind direction, intensity and duration) controlling the transport of eggs to the inner parts of the estuary and the extension of their excursion. This experiment is the first attempt to couple biological and physical information to study fish eggs transport, and to enhance the current knowledge about recruitment of important fisheries resources in southern Brazil.     

Two-dimensional Continuum Modeling Approach to Transportation Problems

The continuum modeling approach to transportation models is now gaining much attention because of its advantages in dealing with dense-network models, macroscopic problems, and initial phase planning. This paper aims to provide a comprehensive review of the development and applications of the two-dimensional continuum modeling approach. The theoretical development and models with specific or arbitrary region configurations are first discussed, and then the applications of the continuum modeling approach to the determination of facility location, route choice, pedestrian flow, and policy and socio-economical analysis are reviewed. Finally, some prospective directions for future research are proposed.     

A study of train dwelling time at the hong kong mass transit railway system

This paper investigates the relationship between the dwelling time of trains and the crowding situations at Mass Transit Railway (MTR) stations in Hong Kong. Regression models were established for the dwelling delays of trains due to congestion at stations, and a simulation model making use of the Monte-Carlo technique is developed to assess the reliability of the estimated train dwelling time. Therefore, the distribution and the confidence interval of the train dwelling time can be predicted on the basis of observed boarding and alighting distributions.     

Ridership estimation for short-range transit planning

The objective of this research was to develop a simple transit ridership estimation model system for short-range planning. The main feature of the model system is that it exploits knowledge of transit link volumes which are obtained readily from on-off counts. Extensive use is made of default values for model parameters, taken directly from the transportation literature. The remaining parameters can be derived easily from generally available land-use and socioeconomic data. Expensive household surveys and time-consuming model calibrations are not required. A sequence of simple trip generation, trip distribution and modal split models generate trip-purpose specific transit trip tables, denoted as “trial” trip tables. These trip tables and observed transit link volumes are used in a linear programming model which serves as a correction mechanism. The gain in accuracy is achieved by using the ridership information contained in the transit link volumes. The corrected trip tables may be used in a pivot-point analysis to estimate changes in ridership and revenue. The results of a test application of the model system indicate that it can generate accurate ridership estimates when reliable transit link volumes are available from on-off counts, and when the trial transit trip tables as derived from the first three component models are reasonably accurate.     

Control of traffic in residential neighborhoods: Some considerations for implementation

The effect of motor vehicles upon older neighborhoods has received increasing attention as residents of these areas seek to preserve the quality of life in their neighborhoods. In order to reduce through traffic in residential neighborhoods, numerous techniques have been developed, ranging from turn prohibitions to physical barriers. Since these measures have negative impacts on previous users of the streets, there has been substantial opposition to them. This paper reviews the major areas of conflict as revealed through court challenges.Nine court cases were identified by the researchers. In four, the court decision supported the control measures; in five, the courts decided against the actions. Six of the nine cases are reviewed in this paper. Major legal issues which are identified include the appropriate use of municipal police power, reasonableness in the exercise of police power, the integration of control measures into an overall transportation plan, appropriate consideration of emergency vehicle needs and the rights of access to property, and public participation in the decision. The authors conclude that properly planned and executed diversion strategies can be implemented and can withstand challenges by negatively affected parties.The opinions, findings, and conclusions expressed or implied in this paper are those of the authors only. They are not necessarily those of the Federal Highway Administration.     

Comparative Analysis of Dynamic ShuttleSystem and the Existing High Speed Ground Transportation Systems

The dynamic shuttle system treated in this paper consists of main line trains traveling at a fixed speed. Passengers are shuttled to and from these fixed speed trains by means of shuttle cars. The shuttle cars can provide local service and thus alleviating the need for stations along the route of the main line trains. The main line trains have a peak volume, depending upon operating speed which is an order of magnitude greater than existing modes. They provide high speed service to travelers in the belt traversed by the trains.     

Efficiency of the public and private bus transport sectors in Sri Lanka

The public and private bus sectors are in direct competition in most bus routes in Sri Lanka. Consequently, Sri Lanka is an ideal location to study their relative efficiencies. Five dimensions of transit performance are analyzed for comparing the relative efficiencies of the two sectors: cost efficiency, labour efficiency, input efficiency, revenue generation and safety. Productivity ratios are utilized for measuring the dimensions of transit performance. The productivity ratios for cost efficiency, labour efficiency in terms of total staff, input efficiency, revenue generation and safety in terms of accidents per bus showed the private bus transport sector to be more efficient than the public bus transport sector.